Method and Sorbant for Removing Contaminates From Water

Abstract

A method for removing dissolved contaminants, such as arsenate, from water by the step of contacting a sorbant with the water, the sorbant comprising more than ten weight percent of an oxide of titanium and more than one tenth weight percent of a sulfate salt, such as calcium sulfate, having a solubility in water at room temperature of less than 0.5 grams per liter of water, wherein the oxide of titanium is primarily titanium dioxide.

1 . A method for removing dissolved contaminants from water, comprising the step of contacting a sorbant with the water, the sorbant comprising more than twenty weight percent titanium on an elemental analysis basis and more than 2 weight percent of a sulfate salt having a solubility in water at room temperature of less than 0.5 grams per liter of water, wherein the oxide of titanium is primarily titanium dioxide. 
     
     
         2 - 3 . (canceled) 
     
     
         4 . The method of  claim 1 , wherein the sorbant comprises more than 5 percent by weight of the sulfate salt. 
     
     
         5 . The method of  claim 1 , wherein the sorbant comprises more than 10 percent by weight of the sulfate salt. 
     
     
         6 . The method of claim  2 , wherein the sulfate salt is a calcium sulfate salt. 
     
     
         7 . The method of  claim 6 , wherein the sorbant comprises less than 5% calcium on an elemental analysis basis by weight. 
     
     
         8 - 18 . (canceled) 
     
     
         19 . The method of  claim 1 , wherein the sorbant comprises more than forty weight percent titanium on an elemental analysis basis, more than one weight percent sulfur on an elemental analysis basis, and less than five weight percent calcium on an elemental analysis basis. 
     
     
         20 . The method of  claim 19 , wherein the sorbant comprises more than two weight percent sulfur on an elemental analysis basis. 
     
     
         21 - 23 . (canceled) 
     
     
         24 . A sorbant comprising more than twenty weight percent titanium on an elemental analysis basis, and more than 2 weight percent of a sulfate salt having a solubility in water at room temperature of less than 0.5 grams per liter of water, wherein the oxide of titanium is primarily titanium dioxide. 
     
     
         25 - 29 . (canceled) 
     
     
         30 . The method of  claim 1  wherein the sorbant is formed by adding lime and water to uncalcined titanium dioxide. 
     
     
         31 . The method of  claim 1  where the step of contacting the sorbant with water comprises flowing water through a bed of the sorbant. 
     
     
         32 . The sorbant of  claim 24  comprising more than 5 weight percent of the sulfate salt. 
     
     
         33 . The sorbant of  claim 24  comprising more than 10 weight percent of the sulfate salt. 
     
     
         34 . The sorbant of  claim 24  wherein the sulfate salt comprises calcium sulfate. 
     
     
         35 . The sorbant of  claim 24  comprising less than five weight percent calcium on an elemental analysis basis. 
     
     
         36 . The sorbant of  claim 24  comprising more than forty weight percent titanium on an elemental analysis basis, more than one weight percent sulfur on an elemental analysis basis, and less than five weight percent calcium on an elemental analysis basis. 
     
     
         37 . The sorbant of  claim 36  comprising more than two weight percent sulfur on an elemental analysis basis.